Re: free()'ing restrict'ed pointers

On Jul 31, 2:40 pm, s0s...@xxxxxxxxx wrote:
Hi,

A object to which there is a pointer that has been declared 'restrict'
is supposed to be accessed only through that pointer. So is it safe to
call free() with a restricted pointer? Does free() try to access what
in points to in some way?

You are quoting incorrectly what "restrict" means: The data pointed to
may be accessed through the restrict pointer itself, or through a
pointer derived from that pointer. If you have a pointer "int
*restrict p" and call free (p), then the argument to free is derived
from p and is allowed to access the data as much as it likes.

Now what is wrong is the following:

int* p = malloc (100);
int* restrict q = p;

p [0] = 1;
free (q);

(the call free (q) is just as wrong as an assignment q [0] = 2 or just
reading q [0] would be).
.

Relevant Pages

  • Re: restrict in plain English?
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  • Re: Commenting the source code.
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  • Re: free()ing restricted pointers
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  • Re: Using restricted pointers with newly allocated arrays/structures
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    (comp.std.c)
  • Re: Inconsistent Program Results
    ... void rdinpt; ... The return type of main is int, so this should be int main, ... to increment a NULL pointer, that's undefined behavior, so anything can ... against this by making sure that restrict is not NULL, ...
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